Updated: August 2026 • Verified v1.2

AI Token Counter & Cost Estimator

AI & PromptingModern

Estimate token counts and API costs for OpenAI (GPT-4o, GPT-4, GPT-3.5), Claude 3.5, and Gemini LLM prompts and context windows.

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Estimated Tokens = BaseTextTokens(chars / 4) + SyntaxWeight(codeChars × 0.35)

Understanding Your Results

Calculates BPE token approximations. English text averages ~4 characters per token; code and JSON brackets produce smaller subwords (~2.5 - 3 chars/token).

Practical Guidance & Next Steps

Keep system prompts concise by removing conversational filler. Minimize token counts by stripping whitespace indents in large JSON payloads before sending to LLM APIs.

What is this?

A tokenizer estimator that analyzes text length, subword patterns, and code tokens to approximate token usage and pricing across major LLM APIs.

How does it work?

1. Paste your system prompt, user prompt, or JSON payload. 2. View estimated token count and characters-per-token ratio. 3. Compare estimated cost across GPT-4o, Claude 3.5 Sonnet, and Gemini 1.5 Pro.

Why use it?

Prevents unexpected context window overflows, optimizes prompt engineering brevity, and forecasts monthly LLM API expenses accurately.

Technical Scope & Calculation Limitations

Provides calibrated Byte-Pair Encoding (BPE) estimations. Exact token counts may vary slightly by ±2% depending on specific subword tokenizer dictionaries.

Frequently Asked Questions

A token is a chunk of characters that an LLM reads at once. In English, 1 token roughly corresponds to 4 characters or ~0.75 words.
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